This is the fourth in a series on fantasy defenses. I started with an overview of trends in defensive fantasy scoring , then week looked at whether a defense’s “base” alignment affected its fantasy scoring, and most recently, the impact of changing coordinators and alignments. Now I want to see if changing head coaches makes a difference, especially based on their background as offensive or defensive assistants.
A quick review of my methods: I’m studying from 2002 to the present and only looking at Tm Defensive (Tm D) fantasy scoring, NOT defense AND special teams (D/ST) scoring. Here’s the scoring system I’m using:
- Interceptions = 2 FP
- Fumble Recoveries by the Defense = 2 FP
- Sacks = 1 FP
- Safeties = 2 FP
- Interception and Fumble Recovery Returns TDs = 6 FP
- 0 Points Allowed (PA) = 12 FP
- 2-7 PA = 8 FP
- 8-12 PA = 4 FP
- 13-17 PA = 2 FP (note NFFC scoring for PA may change for 2019)
All statistics in this study come from profootballreference.com’s (PFR) invaluable Play Index.
Now, it would make sense that bringing in a head coach with a defensive background would help a fantasy defense. He’ll put emphasis on improving the personnel there while an guy who learned his trade on the offensive side of the ball is going to be more focused on improving the offensive talent. And probably the particular coach was hired because the team needed help on “his” side of the ball.
In fact, that last hypothesis is wrong, at least from a fantasy standpoint. Teams that hired a “defensive” head coach averaged 111 FP the year before bringing him in, compared to 108 FP for teams hiring an offensive mind to run the show. What about the first one?
Since 2002, 120 head coaches have been hired by NFL teams:
The pattern before 2012 is not clear, because 32 of those hires had a defensive background versus 33 from the offensive side: an even split, which one would expect. But from 2013, the NFL has leaned heavily to hiring offensive-minded HCs: 36 of them compared to just 18 with a defensive resume. And that if even with the 2015 season which leaned very heavily to the defensive side. The chart ignores the one special teams coordinator who got a HC job, John Harbaugh with the Ravens starting in 2008 (although he did coach DBs in 2007).
(Moneyball thought: if everyone is out hiring offensive coordinators or assistants or marginal college coaches with offensive backgrounds, then there are probably some DCs who should be HCs who are getting overlooked. Don’t even get me started on ST coordinators).
Here’s the impact of those new hires on their Tm D’s fantasy points:
Again, the results are counter-intuitive: new HCs with a background in offense improve their fantasy defenses substantially more (18 FP on average) than “defensive” HCs (only 5 FP). For reference, remember the average TM D in this period scored 127 FP – making a TM D better is not the same as making it good.
To show how HC’s affect their Tm D FP over time, I need to normalize Tm D scoring. One of the problems in analyzing Tm D scoring is in this graph:
A TM D scoring 116 FP in 2002 was a bad fantasy option; in 2018 it was an average one. It’s important to put each defense in the context of its own season by normalizing its FP – that is, dividing the FP it scored by the average FP for that year. For this study, I chose to express that normalized score as a percentage, where 100% is an average defense; under 100% is below average and over 100% is above average. Doing that, a 2002 Tm D with 116 FP has a normalized FP of 87%. The best fantasy defense since 2002 by this measure is the 2017 Jaguars, who had a 186% normalized FP.
Even normalizing FP, Offensive HCs have better fantasy Tm Ds in their first season:
But in their 2nd year, Defensive HCs are fielding better (although still below average) defenses than the offensive-minded HCs. After that it fluctuates, although Year 6 is very bad for Defensive HCs (even Bill Belichick had an 87% that year in his tenure). From Year 8 on, Defensive HCs are never worse than Offensive HCs and most, from both sides of the ball, are better than average. In fact, head coaches with 8+ years of tenure have averaged 106% normalized FP – that’s about Tm D12.
For offensive HCs there is a sweet spot from about Year 6 to 11 where they average 106%. For defensive guys, it’s later. I stopped the graph at Year 13 as only 2 offensive HCs and 4 defensive HCs lasted that long, but defensive HCs average 111% (around Tm D10) from Year 9 on. Some of this is no doubt survivor bias – and having Belichick as one of the survivors doesn’t hurt. But if you want to play this angle, Belichick, Pete Carroll, and Mike Tomlin are all in Year 9+ in 2019. The offensive HCs in the Year 6 to 11 range are Andy Reid, Sean Payton, and Jason Garrett.
And if you want to avoid a defensive HC’s Tm D in his 6th season, Mike Zimmer and the Vikings are in that spot in 2019. New HCs with a defensive background have averaged 87% normalized FP, so MIA (Brian Flores) and DEN (Vic Fangio) don’t look like good bets on that basis.
Of course, these are just historical averages. That means half of all coaches will beat them and half will fall beneath them. And there is always the stockbrokers mantra: past performance is no guarantee of future performance. I wouldn’t make my decisions solely on these numbers, but I wouldn’t ignore them either. Just another factor to consider.
